scholarly journals Determination of Iron Valence States Around Pits and the Influence of Fe3+ on the Pitting Corrosion of 304 Stainless Steel

Materials ◽  
2020 ◽  
Vol 13 (3) ◽  
pp. 726
Author(s):  
Zhang ◽  
Du ◽  
Wang ◽  
Zhao ◽  
Zhou
Keyword(s):  
Stainless Steel ◽  
Corrosion Rate ◽  
Pitting Corrosion ◽  
Ph Value ◽  
Ion Concentration ◽  
304 Stainless Steel ◽  
Solution Ph ◽  
Valence States ◽  
The One ◽  
Iron Valence

Potassium ferricyanide and potassium ferrocyanide were used to observe and monitor the pitting corrosion of 304 stainless steel (SS) at anodic polarization in situ. The results show that there are Fe3+ ions around the corrosion pit when pitting occurs on 304 SS in NaCl aqueous solution. The effect of Fe3+ surrounded pits on the pitting corrosion was also studied by testing the electrochemical behavior of 304 SS in different Fe3+/Fe2+ solutions. The presence of Fe3+ leads to the positive shift of corrosion potential and the increase of corrosion rate of 304 SS. There are two possible reasons for this phenomenon. On the one hand, Fe3+ hydrolysis results in the decrease of pH value of solution. At the same iron ion concentration, the higher the Fe3+ ion concentration, the lower the solution pH value. On the other hand, Fe3+ may reduce on the electrode surface. The decrease of solution pH and the reduction of Fe3+ resulted in the acceleration of the corrosion rate.

Research on the Failure Mechanism of Pitting Corrosion of the 304 Stainless Steel in Chloride Ions Environment

2012 ◽  
Vol 502 ◽  
pp. 12-16
Author(s):  
Yi Pan ◽  
Rong Fa Chen ◽  
Du Xiong Wang ◽  
Guo Sheng Cai ◽  
Xian Liang Zhang ◽  
...  
Keyword(s):  
Stainless Steel ◽  
Corrosion Rate ◽  
Failure Mechanism ◽  
Pitting Corrosion ◽  
Chloride Ion ◽  
Chloride Ions ◽  
304 Stainless Steel ◽  
Cr Content ◽  
Experiment Method ◽  
Ion Impact

The Mechanism of 304 Stainless Steel Pitting Corrosion Was Researched in Chloride Ions Environment. the Metallographic Microstructure of Areas near the Pitting Corrosion and Far Away from the Pitting Corrosion Were Observed by the Metallographic Experiment；Cr Content of the Sample Was Determined by EDXRF, to Prove Chloride Ion Impact on the Element Cr of 304 Stainless Steel. Finally, Corrosion Rate of Specimens Was Determined by Piecewise Experiment Method to Prove Otherness for Corrosion Rate in Different Period of 304 Stainless Steel in Chloride Ions Environment.

Investigation on Acoustic Emission Characteristics from Corrosion of Conventional Materials of Primary Pipe in Nuclear Power Plants

2014 ◽  
Vol 487 ◽  
pp. 54-57 ◽  
Author(s):  
Meng Yu Chai ◽  
Li Chan Li ◽  
Wen Jie Bai ◽  
Quan Duan
Keyword(s):  
Stainless Steel ◽  
Acoustic Emission ◽  
Pitting Corrosion ◽  
Nuclear Power ◽  
Power Plants ◽  
Nuclear Power Plants ◽  
316L Stainless Steel ◽  
304 Stainless Steel ◽  
Emission Characteristics ◽  
Research Topics

304 stainless steel and 316L stainless steel are conventional materials of primary pipeline in nuclear power plants. The present work is to summarize the acoustic emission (AE) characteristics in the process of pitting corrosion of 304 stainless steel, intergranular corrosion of 316L stainless steel and weldments of 316L stainless steel. The work also discussed the current shortcomings and problems of research. At last we proposed the coming possible research topics and directions.

A Study on Warm Micro Backward Extrusion of SUS 304 Stainless Steel

2011 ◽  
Vol 486 ◽  
pp. 139-142
Author(s):  
Chao Cheng Chang ◽  
Dinh Hiep Nguyen ◽  
Hsin Sheng Hsiao
Keyword(s):  
Stainless Steel ◽  
Metal Forming ◽  
Material Flow ◽  
Elevated Temperatures ◽  
304 Stainless Steel ◽  
Electrical Heater ◽  
Backward Extrusion ◽  
Water Based ◽  
Inner Diameter ◽  
The One

A metal forming system comprising an electrical heater, capable of conducting processes at elevated temperatures, was developed to perform micro backward extrusion processes of SUS 304 stainless steel. Two punches with diameters of 1.6 mm and 1.8 mm were used to extrude the billets inside the die with an inner diameter of 2 mm. All processes were lubricated with water-based graphite and conducted under isothermal conditions at 400 °C. The results show that the developed extrusion system can be used to produce the stainless steel components with a micro cup-shaped profile. Moreover, the variation in the rim height of the cups produced by the 1.8 mm diameter punch is greater than the one by the 1.6 mm diameter punch. The results show that a decrease in the clearance between the punch and die could lead to an increase in the inhomogeneity of material flow in the micro backward extrusion processes.

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